Water-tube boiler.



No. 772,340. v PATENTED oo'r. 1a, 1904.

J. GOWAN.

WATER TUBE BOILER.

APPLICATION FILED JULY 22, 1902.

N0 MODEL.

2 s nnnrs-snnm 1.

No.772,340. I PATBNTED 00111;,1904. J. GOWAN.

WATER TUBE BOILER.

APPLICATION FILED JULY 22, 1902. l no MODEL. 2 snnms-snnnm.

UNITED STATES Patented October 18, 1904.

PATENT OFFICE.

WATER-TUBE BOILER.

SPECIFICATION forming part of Letters Patent N0. 772,310, dated October18, 1904:. Original application filed October 3, 1901, Serial No.77,456. Divided and this application filed July 22, 1902. Serial To allwhom it may concern.-

Be it known that I, JOHN CowAN, managing director of the Stirling BoilerCompany, Limited, a subject of the King of Great Britain and Ireland,residing at 2 St. Andrews Square, Edinburgh, Scotland, have inventedcertain new and useful Improvements in Water-Tube Boilers, (for which Ihave made application for Letters Patent in Great Britain, No. 9, 924,dated May 13, 1901; in Germany, dated September 30, 1901; in Russia, No.15,281, dated October 3, [September 20,] 1901, and for which I haveobtained a patent inFrance, No. 31 1, 561, dated September 28, 1901,) ofwhich the following is a specification.

This invention is a division of the apparatus disclosed in applicationfor Letters Patent of the United States, Serial No. 7 7 ,456, filedOctober 3, 1901.

My invention relates to water-tube boilers, especially to the Stirlingboiler of the construction known as the W type. In this type of boilerthe three steam and water drums of the boiler are connected by banks oftubes with the two lower water-drums, a considerable space between thesetwo drums being necessary.

In many cases, particularly where boilers are placed in vessels wherespace'is valuable and a reduction in weight desirable, anysaving thatcan be effected in the space occupied by and in the weight of the boilerwithout causing a loss of efliciency is of great importance.

It is the object of my invention to reduce the weight of the boiler aswell as the space which the boiler occupies while maintaining itsefficiency and water circulation and to so provide for the circulationof the water that no matter how much the tiring of the boiler be forcedthere will be no danger of burning out the water-tubes or of priming.

My invention consists in providing the boiler with one lower water-drumdivided by a longitudinal partition into two water-spaces communicatingwith each other at the upper part of the partition, the feed-drum beingdivided longitudinally, whereby the entering feed- (No model.)

' water is prevented from freely mingling with the hotter circulatingwater until it reaches the lower water-drum, which is connected by banksof tubes with each steam and water space above, and in so proportioningthe tubecirculation areas as to prevent burning out of the tubes andpriming.

Referring now to the accompanying drawings, Figure 1 is a sectional sideelevation of a Stirling boiler with my invention applied. Fig. 2 is anend view of the same, the left-hand half being a section on the line :000 of Fig. 1 with the half-grate removed.

In carrying my invention into effect according to one modification Iform the boiler with three upper steam and water drums a, b, and c, andI connect each of them to a lower waterdrum (Z by banks of tubes 0, f,and g. The back steam and water drum '0, into which the feed-water isdelivered, is connected by a nearly-vertical bank of tubes g to thelower water-drum d. The central drum 6 is connected by an inclined bankof tubes f, while the front drum (0 is connected by a more sloping bankof tubes 0. The drums a and b are also connected together by banks oftubes .9 and t, the former entering the drums below the normalwater-level and the latter above it. The steam-spaces of the drums .7)and 0 are likewise connected by a bank of tubes 14.

Inside the lower water-drum cl I place a longitudinal partition h,dividing the drum into two water-spaces j and Z0, and I place thispartition so that the banks of tubes 0 and f are led into the space andthe bank of tubes g is led into the space 7a. In some cases it ispreferable to arrange the partition to divide the central bank of tubes,so that halfof its tubes and the front bank of tubes communicate withthe space and the remainder of the tubes communicate with the space in.Passages m are provided in the upper part of the partition to permitintercommunication between these two water-spaces j and k. By employingone lower water-drum and dividing it into two spaces in this manner I amable to dispense with one of the two lower water-drums formerly used,thus reducing downtake.

the total weight and cost of the boiler and greatly reducing thefloor-space occupied. I have found, however, that in boilers providedwith my divided lower water drum when the boiler is forced there is atendency for the water to pile in the two steam and water drums a andbnearest to the furnace and to lower the level in the feed drum 0. ThisI found was due to the fact that the half of the central bank of tubes fnearest the furnace underthese conditions acts as an uptake for thewater, leaving only the other half of the central bank of tubes to actas a Circulation was thus to a certain extent retarded. I have found byexperiment, however, that this difficulty may be effectually overcome,and the water circulation and efliciency of the boiler greatly improvedby the following simple device.

Vithin the steam and water drum 0, which acts as a feed-drum, I place alongitudinal partition n, preferably fixed to the bottom of the drum, soas to divide the bank of tubes 9 into two banks 0 and p. I also formdirect communication between the side of the feed-water drum 0 nearestthe furnace and the central steam and waterdrum b by one or more rows oftubes 9, arranged below the level of the water in these drums and ofsuch capacity that the water-level in the front half of the feed-drum 0will remain practically the same as in the front drums a and b at alltimes. The feedwater pipe 9' delivers into the feed-drum on the side ofthe partition remote from the furnace, I make the upper edge of thepartition 12 rise a suitable height above the normal water-level, sothatwhen under forcing piling of the water tends to take place'in thefront and middle drums at and b the water in the front part of the drum0 will be correspondingly raised and will flow over into the back halfof this drum, which forms the feeddrum proper.

I have made careful experiments on a boiler thus constructed and havefound that it may be very heavily forced without the least detriment toits water circulation, for as soon as there is any tendency for thelevel of the water to rise in either or both of the steam and waterdrums nearest the furnace a rapid How of water occurs from these drumsto the feed-water drum, since all of them are in direct communicationwith each other. Further equilization of the water-level takes place byoverflow from the front halfof the back drum 0 into the back half, Thesingle lower waterdrum d is thus made to satisfactorily perform thefunctions of the two drums formerly used.

A further important advantage obtained by a boiler constructed accordingto my invention is that practically all the feed-water is kept separatefrom the circulating water of the boiler until it has passed down thebank of tubes most remote from the furnace into the coolest and mostquiescent part Z: of the lower water-drum (Z. By treating the feedwaterin this manner before allowing it to mix freely with the circulatingwater most of the incrustation-forming compounds and mud which itcontains are deposited before the water reaches the hottest bank oftubes 6 nearest the furnace.

The mud-drum should be provided with the neceissary blow-off valve andmandoor, as desire In applying my boiler to marine purposes I mayprovide the steam and water drums with cross-baffle plates 1), Fig. 2,to assist in preventing serious commotion of the water due to theunsteady motion of the vessel.

Having now described my invention, what I claim as new, and desire tosecure by Letters Patent, is

A water-tube boiler for marine and other purposes, having incombination, a plurality of steam and water drums, a single lowerwater-drum a bank of tubes leading from each of the steam and waterdrums to the lower water-drum; a partition in lower drum, said partitionhaving openings near its upper endand being arranged to provide aquiescent space for settling of mud and also suitaby deflect thecirculating water through the tubes in the rear bank; a partition in thesteam and water drum most remote from the fire dividing the same intocompartments communicating with each other over the top of thepartition; tubes connecting the front compartment of said partitionedsteam and water drum and the adjacent steam and water drum, saidconnecting-tubes beingarranged below the water-level, and means forfeeding feedwater into the rear compartment of the partitioned steam andwater drum, substantially as described.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

JOHN COW AN.

Witnesses:

ANDREW SMITH, P. A. MAO BRAQUE.

